1. Field of the Invention
The subject of the present invention is a fuel delivery unit that can be inserted into a fuel tank of a motor vehicle, comprising a swirl pot, a flange for closing off an opening in the fuel tank, at least one support element designed as a hollow profile arranged between the flange and the swirl pot that preloads the swirl pot against the base of the fuel tank comprising a filling level sensor arranged on the swirl pot.
2. Description of the Prior Art
Fuel delivery units of this type are frequently inserted into fuel tanks of modern motor vehicles and have therefore long been known. The support elements are generally tubes or rods which are pressed into receptacles arranged on a flange. A swirl pot has bores that correspond to the support elements in which the support elements slide. The swirl pot is pre-loaded against the base of the fuel tank by at least one spring element arranged around a support element. The pre-loading provides a base reference for the filling level sensor, since the filling level sensor for determining the fuel quantity is often arranged on the swirl pot. Lack of a base reference would lead to an erroneous filling level measurement, since the base of the fuel tank bends as a function of the weight of the fuel, as a result of which the spacing between the base and the upper boundary wall of the fuel tank is dependent on the filling level in the fuel tank.
DE 199 42 379 A1 discloses a device for measuring filling levels by ultrasound. For better signal transmission and signal evaluation, a rigid measuring tube is provided in the fuel tank. Therefore, both a filling-level-dependent change in the spacing between the base and the upper boundary wall of the fuel tank and also production-related tolerances in the range of several millimeters have the result that the measuring tube cannot be arranged optimally up to directly below the upper boundary wall of the fuel tank. The sound waves and their reflections must therefore run through the fuel tank in a partially unguided manner.